CA1291369C

CA1291369C - Water pump

Info

Publication number: CA1291369C
Application number: CA000519034A
Authority: CA
Inventors: Samuel Dick
Original assignee: R.S.D. LIMITED
Current assignee: Rsd Ltd
Priority date: 1986-09-24
Filing date: 1986-09-24
Publication date: 1991-10-29
Anticipated expiration: 2008-10-29

Abstract

C A N A D A

ROGERS, BERESKIN & PARR

TITLE: WATER PUMP

INVENTOR: SAMUEL DICK

ABSTRACT OF THE DISCLOSURE

A pump has a casing defining a pumping chamber. A liquid inlet enabling liquid to enter the casing extends through the casing and includes a one-way inlet valve. A liquid outlet tube extends through the top of the casing to a location adjacent the bottom thereof. A U-shape control tube has first and second limbs joined at their lower ends, with the first limb located within and extending along the outlet tube and with the second limb located in the casing extending vertically. The top of the second limb is below the top of the casing. A first air inlet opens into the chamber. When air is supplied to the chamber and the chamber is submersed in sufficient liquid, the liquid inlet and U-shape control tube control cyclic operation of the pump, causing liquid to be pumped out of the liquid outlet.

Description

~3~

2 ~-This invention relates to a pump. This invention more particularly, but not exclusi~el~, relates to a pump intended for use as a sump pump and driven by air.
There are numerous installations, machines etc, in which there is a sump for the accumulation of a variety of liquids.
Normally, it is necessar~ to provide a pump at the bottom of the sump, to periodically pump out the l:iquid. Fxequently, the li~uids that are accumulate are waste liquids, which can have a var~ing composition. Also, the liquids frequently contain corrosive matter, and.can transport a variety of solid material, that tends to cloy pumps etc. Accordingly, it is desirable to provide a pump, for use in a sump, that is of a simple, robust construction. The pump should be capable of being designed to withstand a variety of corrosive materials, and should be capable of operating, even when the liquid contains a large amount of solid or particulate material.
A wide variety of designs have been proposed for use in sumps. Applicant is aware of the following patents relating to pump design and the like:

3,898,018 Weis 3,847,508 Mowen 1,279,580 Peters 1,499,589 Navin 237,594 Russia 162,838 France 344,984 France 541,953 United Kingdom The U.S. patents to Weis and Mowen and the British patent to Bolton all dislose a similar mechanism. This type of mechanism includes a closed housing having an inlet for compressed air, and 313~

a second inlet for the liquid to be pumped. A tube extends from near the bottom of the vessel through the housing, to provide an outlet. A U-tube has one limb which opens near the top of the vessel within the housing, and another limb which is connected at its upper end to the outlet pipe near the top of the housing. This arrangement of the outlet pipe and the U-tube provides a valve arrangement for controlliny the out flow of liquid. When the housing has become full with liquid, it overflows into the U-tube to close the passageway for air. As a consequence, air supplied to the housing builds up pressure to force the liquid out through the outlet. This continues, until the level of liquid has fallen in the U-tube sufficiently to enable the air to clear the U-tube Gf liquid. Thereupon, air can then flow out through the U-tube to the autlet, venting the pressure in the housing. The housing can then fill with liquid again.
Whilst this type o~ construction does indeed provide a simple valve arrangement j for controlling the cyclic operation of the pump, it has some dlsadvantages. A relativel~ complex construction is required, to attach the U-tube to the outlet tube.
Thus, as shown in the WeLs patent, the outlet tube has to be provided with a horizontally extending short connecting tube of smaller diameter. A separate elbow then has to be provided to connect this horizontal tube to one limb of the U-tube.
This also introduces an additional bend into the U-tube construction. This~makes the U-tube more prone to clogging, and it is to be appreciated that, if it becomes clogged, then the pump will cease operating. This is important, when dealing with ~l~9~L;369 fluids containing a large amount and variety of solid material, such as sewage. In such cases, it is important that the pump should be as simple as possible, with as few bends in the pipe work, to reduce the possibility of clogging.
In accordance with the present invention, there is provided a pump comprising: a casing, which defines a first, pumping chamber; a first, liquid inlet for liquid to be pumped, extending through the casing and including a first liquid inlet valve that only permits liquid to flow into the ~hamber; a first li~uid outlet comprising an outlet tube e~tending through the top of the ca.sing to a location ad]acent the bottom of the chamber; a U-shape control tube, having first and second limbs joined at their lower ends, with the first limb located within and extending along the outlet tube, and with the second limb located in the casing extending generally vertically, the top of the second limb being below the top of the casing; and a first air inlet which opens into the chamber; whereby, in use, when submerged in sufficient liquid and when air is supplied to the first air inlet, the li~uid inlet and the U-shape control tube control the cyclic operation of the pump to cause liquid to be pumped out through the first, liquid outlet.
In the construction of the present invention, there is no necessity to provide an elbow or angle connector at the top of the U-tube. Instead, since one limb of the U-shape control tube is located within the outlet tube, it can simply open within the outlet tube, and does not require any positive connection.
The U-shape control tube then simply requires the bend at the .

~l ~g~3~i~3 bottom to join the two limbs together. If desired, the U-shape control tube can be formed simply by bendiny from a single length of tubing. Also, if desired, the U-shape control tube can be mounted separately from the outlet t:ube, which ma~ prove 5 advantageous for some purposes.
As the U-shape control tube now ~ust includes a bend at its lower end joining the two limbs together, it is e~pected to be much less prone to clogging. This should make the pump better suited for use with liquids containing solid material.
Also, for some uses, it may enable a smaller section U-shape control tube to be used, without fear of the tube becoming clogged or blocked. This saves on material. Additionally, where a small diameter control tube is used, the consumption of air is reduced. Ik is to be noted that in this type of pump design, there is a continuous through flow of air, when the liquid around the pump falls below a certain level, unless some addltional exterior valve means are provided. It is therefore desirable, to minimize the through flow of air that occurs through the control tube! in the absence of sufficient liquid. If desired, the pump can be provided with a mechanism, such as a siphon, to ensure that the pump only operates when the liquid level around the pump has reached a sufficient depth, and to effectively switch off the pump when the liquid level falls below a lower level. Such a siphon should be placed above the top of the pump casing. Otherwise, the pump can continuouslv switch itself on and off between two relatively close levels.
Where a siphon is provided, the top of the siphon effectively ~L~9~3~.9 determines the level re~uired to activate the pump, whilst the bottom end of a free limb of the siphon will determine a lower switching level. Once operation commences, then liquid will be pumped continuously, until the li~uid level falls below the bottom of the free limb of the siphon.
Whilst the pump defined above has a single chamber, it is possible for the pump to include two chambers. With a two chamber pump, greater reliability can be obtained. Also, it may be possible to join the two outlets together by a valve arrangement, which orlly permits one chamber to exhaust at a time. By this means, it should be possible to control the operation of the two chambers, so as to give an almost continuous, smooth output. Alternatively, it might be possib~le to achieve the same effect, by providing a valve arrangement in the air lS supply line, which ensures that air is only supplied to the chamber, which is emptying through the outlet. By this means again, an almost smooth, continous output should be provided, whilst also saving on air consumed, as no air is vented through the chamber which is filling.
For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawing, which shows a vertical section through a pump in accordance with a preferred embodiment of the present invention.
In the drawing, there is shown a pump, generally denoted by the reference 1, located in a sump 2. The sump 2 is shown schematically, and it i5 to be appreciated that the pump 1 313~,9 can be located anywhere, which is of sufficient size to accomodate it. The sump 2 is shown partially filled with water to a level indicated at 3.
The pump 1 is a single chamber pump, having a chamber 6n The chamber 6 is defined by a casing 10, which can be formed in any suitable manner. The materials of the casing, and other components of the pump 1 should be chosen for the particular application. Thus, for corrosive li~uids, appropriate materials should be chosen.
For the chamber 6, there is a first, li~uid inlet 14.
Here, the first liquid inlet 14 is a tube extending downwardly through the top of the casing 10. At the lower end of the water inlet 14, there is a check valve 16, shown schematically. This check valve 16 only permits li~uid to flow down through the inlet 14 into the chamber 6. The check valve 16 could comprise a simple ball and a conical seat, the ball being buoyant, so that it naturally tends to bear against the seat. A li~uid outlet 18 comprises a tube extending from near the bottom of the first chamber 6 out through the top of the casing 10. An air inlet 20 opens into the top of the chamber 6, and is connected to an air control valve 22. This air control valve 22 is supplied with compressed air through a line 24. Further, the air control valve 22 is secured in position and is operated by a float 26 on the end of an arm, in known manner.
Within the chamber 6, there is also a U-shape control tube 28. Here, the bottom of the U-shape control tube 28 rests on the bottom of the casing 10. The control tube 28 includes ~t~1~3~i9 first and second limbs 30, 32. The irst limb 30 extends up inside the outlet tube 18, so that its upper end opens into the outlet tube 18. The second limb 32 is of corresponding length, but it extends upwardly outside the outlet tube 18. The second limb 32 opens into the chamber 6. Whllst the control tube 28 is shown with two limbs 30, 32, which are relatively close together, it is to be appreciated that various configurations can be emplo~ed. Thus, although the first limb 30 is shown close to one side of the outlet tube 18, it could instead be provided coaxially within the outlet tube 18. However, partiaularly for liquids containing solid matter, it is preierred for the first limb 30 to be close against the side of the outlet tube 18, to leave as large an area of the outlet tube 18 free from obstruction as possible. Similarly, the second limb 32 simply need open at the appropriate height within the chamber 6. It does not have to be close to the outlet tube 18. For example, the second limb 32 could be secured to a side wall of the casing 10.
The operation of the pump l will now be described. The pump l relies for operation upon compressed air supplied through the line 24. Since this supply is controlled by the valve 22, operation cannot commence until there is a sufficient depth of liquid. When the liquid reaches a sufficient depth, the float 26 will be lifted up, to open the valve 22. Thereupon, compressed air will be supplied through the line 24 to the chamber 6. When sufficient liquid is present, as indicated by the line 3, then the chamber 6 will fill with liquid to above the height of the second limb 32 of the control tube 28. As a consequence, the control tube 28 will fill with llqllid. This will prevent there being any clear passage throuyh the chamber 6 for compressed air supplied through the line 24. Air pressure will build up in the chamber, so as to force liquid out through the ou-tlet tube 5 18. As the liquid level in the chamber 6 falls, the level of liquid in the second limb 32 will be maintained at the same level.
I,iquid will be pumped out the chamber 6, until the outlet tube 18 is cleared of ~luid. As is known, during this part of the cycle, the pressure in the chamber 6, will maintain the check valve 16, to prevent back flow out throu~h the inlet 14. Once the chamber 6 has been emptied, the U-shape control tube 28 will be empty.
As a consequence, there will be a clear, unobstructed path for compressed air out through the tube 28. In the absence of excess pressure in the chamber 6, the valve 16 will open, to permit the lS chamber 6 to fill with fluid again. It will fill with ~luid, until the fluid level reaches the top of the second limb 32. At this point, the control tube 28 will be filled with liquid, to close off the part for the compressed air. The cycle will then be ready to commence again, with compressed air pressure building up in the chamber 6, to vent the contents through the outlet tube 18.
It is to be appreciated that the U-shape control tube 28 can be of simple construction. The inlet 14 and outlet tube 18 are shown with collars at their upper ends, for attachment to additional piping if required. However, the control tube 28 unlike known designs, does not have to be attached to any other pipe work. As a consequence, it can be simply formed by bending 3~

from a single length of piping. Also, no consideration has to be given to the connection between the control tube 28 and the outlet tube 18, so that they can be formed from entirely dissimilar materials etc.
It is expected that the pump of the present invention should be particularly suitable for pumping fluids containing a large amount of solid matter, such as sewage. The simple inlet valve 16 should be relatively free from jamming, due to the presence of a solid material. Even if it is held open partly during one cycle, it should ~ree itself of the solid matter during the next cycle. The simple U-shape control tube 28, having no moving parts, should be free also from jamming. For each cycle, the only quantity of liquid that passes through the ..
, control tube 28 is the volume of the tube 28. The vclume of the chamber 6 is largely pumped out through the outlet duct 18.
By way of example, the drawlng also shows, in broken lines, the possible addltion of a siphon pipe 90. This would be provided for controlling the operation of the pump, and in this case the control valve 22 would be omitted. This does have the disadvantage that, until operation of the pump commences, there would be throughflow of the air through the chamber 6, which might be excessively wasteful in some applications. The syphon pipe 90 is connected to the liquid inlet 14. The syphon pipe 90 axtends between a lower free end 92 and an upper end 94.
It is expected that the si~hon pipe 90 should effectively set lower and upper operating limits at the locations 92, 94. Thus, operation will not commence until the liquid level reaches the top 94 of the siphon pipe 90. When it reaches this level, the siphon pipe 90 will be filled, so that liquid will flow into the chamber 6. The pump will then operate, and reduce the li~uid level. This level will be reduced, until the liquid falls below the lower free end 92 of the siphon pipe 90. At this point, a siphon will be broken, to terminate operation of the pump 1.

Claims

1. A pump comprising: a casing, which defines a first, pumping chamber; a first, liquid inlet for liquid to be pumped, extending through the casing and including a liquid inlet valve that only permits liquid to flow into the chamber; a first liquid outlet comprising an outlet tube extending through the top of the casing to a location adjacent the bottom of the chamber; a U-shape control tube, having first and second limbs joined at their lower ends, with the first limb located within and extending along the outlet tube, and with the second limb located in the casing extending generally vertically, the top of the second limb being below the top of the casing; and a first air inlet opening into the chamber; whereby, in use, when compressed air is supplied to the first air inlet and the pump is submerged in sufficient liquid, the liquid inlet and the U-shape control tube control cyclic operation of the pump to cause liquid to be pumped out through the first, liquid outlet.

2. A pump as claimed in claim 1, wherein the first limb of the U-shape control tube is parallel to the axis of the outlet tube.

3. A pump as claimed in claim 2, wherein the first limb of the control tube is adjacent an interior wall of the outlet tube.

4. A pump as claimed in claim 2, wherein the first limb of the control tube is coaxial with the outlet tube.

5. A pump as claimed in claim 1, 3 or 4, wherein the diameter of the first control tube is uniform, and is less than 1/4 the diameter of the outlet tube.

6. A pump as claimed in claim 1, 3 or 4, wherein the liquid, inlet valve comprises a ball valve.

7. A pump as claimed in claim 1, 3 or 4, which includes an air control valve disposed outside the casing and a float for actuating the air control valve, in dependence upon the surrounding fluid level.

8. A pump as claimed in claim 1, 3 or 4, wherein the first, liquid inlet is connected to a siphon disposed above the casing, which siphon is adapted to set upper and lower operating levels for the pump.